This invention relates to jet drop recording systems, and more particularly to multiple jet recording systems of the type shown for instance in Sweet et al. U.S. Pat. No. 3,373,437, or in Taylor et al. U.S. Pat. No. 3,560,641. In recorders of the type shown in Sweet et al the jets may be arranged in a single row, while in the Taylor et al. patent they are arranged in a plurality of rows. Such jets may also be arranged in a twin row configuration as shown for instance in Mathis U.S. Pat. No. 3,701,998.
In jet drop recording systems of the above mentioned types all of the jets are stimulated at a uniform frequency to create streams of uniformly sized and regularly spaced drops. All drops are generated in proximity to a suitable charging electrode, and selected ones of the drops are impressed with an electrical charge. All of the drops are caused to pass through an electrical deflection field, and those which are charged are deflected and caught by a suitably positioned catcher. Those drops which are not caught proceed down to a drop receiving member for recording an image thereon.
One of the more difficult operating problems encountered by such recording systems has been unsatisfactory operation of the catchers. In general the drops have been caught on a blade, as shown in Rourke U.S. Pat. No. 3,611,422 or on a smooth, flat catching face as shown in the Mathis patent, and then have been sucked into a collection chamber under the urging of a vacuum. Alternatively the drops have been caught on a porous metal catching face as shown in the Sweet et al patent and have been drawn through the porous metal, again under the action of a vacuum.
Catchers of the Sweet type have not been entirely satisfactory due to the tendency of the drops to splatter upon impact thereagainst, and catchers of the Rourke type have been somewhat unsatisfactory because of the tendency of recording liquid to build up on the edge of the blade and drip from the under side thereof. Accordingly the smooth face catcher as shown in Mathis has been the most satisfactory of available catchers, but it too has a problem in that the air currents caused by the continuous sucking action of the vacuum chamber against the recording fluid entrance slot have tended to disturb the trajectories of the uncharged drops. This in turn has degraded the accuracy of the recording system.